Various internal combustion engines, pumps, vacuum pumps, etc. have used rectilinear reciprocating piston system for compressing or conveying a fluid. This rectilinear reciprocating piston system that moves two-way cannot evade one-way force or reaction force when changing the direction of movement. Even if these forces are offset by disposing a number of pistons in a row, there is a limit to offset against the piston forces or their reaction force applied to its main body and crank shaft at individual position.
Accordingly, the conventional rectilinear reciprocating piston system causes vibration and noise due to the rectilinear reciprocating motion of the pistons. In addition, as the rectilinear reciprocating motion of the pistons used in the internal combustion engine's cylinder is changed into a rotating motion through the crank shaft, a resultant force of the forces acting on the lower portions of the pistons each connected to the crank shaft is not zero with respect to the rectilinear reciprocating motion axis,of the pistons, which causes the cylinder to be eccentrically abraded and shortens the life of the whole machine system. A large and rigid component is used in order to assure the safety of the machine body, which makes the machine heavy.